充分发育烟叶失水特性及烘烤失水调控初报

Study on characteristics and control of fully developed tobacco leaf desiccation in curing process

对成熟烟叶采收后失水基本规律及烘烤过程失水与品质研究表明，烟叶失水干燥特征曲线表现出“近等速—减速—再减速”特征，烟叶失水明显减慢的临界含水率在３００％～３５０％区域。烘烤过程失水环境不同，烟叶失水速度可在４．３～２６．８ｇ．ｋｇ－１．ｈ－１之间变异。在皖北烟区若依靠自然通风进行排湿烘烤充分发育烟叶，绑竿密度以每标准竿６０～８０片为宜，而且采用低温低湿烘烤利于烤房内不同棚次烟叶协调失水。在变黄期，烤房底棚烟叶失水量下、中、上三个部位分别以占鲜烟重４０％、３０％、２７％为宜，失水速度平均值下、中、上三个部位可按１１．０、７．５、６．８ｇ．ｋｇ－１．ｈ－１左右调控。若变黄期烟叶失水适宜，定色期失水速度调控的关键是在升温适宜条件下将湿球温度控制在３７～３８℃。

The characteristic curve of tobacco leaf desiccation could be divided into three region:proximal equal velocity,reductive velocity and more reductive velocity.The critical water content was in 300%350% region when desiccation velocity reduced significantly.Due to environmental modification,desiccation velocity could vary from 4.3 to 26.8 g.kg-1.h-1.Proper density of leaves on stick was 60 to 80 pieces per 1.5m.Lower temperature and moisture curingmethod was beneficial to balance the different tier leave desiccation when fully developed tobacco leaves were cured in the updraft barn ventilating and dried by natural convection at the rainy region during the harvest season.During yellowing,desiccation velocity of mature leaves at the lower,middle,upper stalk position cured in the lowest tier of barn could be controlled at about 11.0,7.5,6.8g.kg-1.h-1respectively.If leaves were desiccated properly during yellowing,the key to control desiccation velocity of leaves was that wetbulb temperature at 3738 ung leaf color fixing.